The present invention relates to a process for preparing an aqueous gel which can be prepared at room temperature and has an excellent transparency and a remarkably small separation of water at low temperature as well as at high temperature.
Also, the present invention relates to an improved aqueous gel composition containing perfume or deodorant, in which a perfume used for giving out fragrance or annuling smell is contained in the aqueous gel prepared by utilizing the above-mentioned process. The aqueous gel composition is placed indoors or the inside of a car and the effect of the aqueous gel composition is kept for a long period.
Further, the present invention relates to a lubricant for metal-processing, which is used when metals are rolled, pulled out or cut under cooling or heating, and a method for use thereof.
Several percents by weight of agar is added to water and is dissolved in water with heating. The aqueous solution is cooled to form an aqueous gel in the form of a pudding. An aqueous gel can be obtained in the same manner as in the above-mentioned method by using gelatine, alginic acid, carrageenan, or the like instead of agar.
However, the above-mentioned natural gels require a step of heat-dissolveing. Moreover the obtained gel is fragile and weak, and is remarkably poor in transparency. Also, gelatine has glue odor. An aqueous gel also is obtained by adding boric acid or borax to aqueous polyvinyl alcohol solution, but the aqueous gel is remarkably weak and has a defect that the gel releases water (hereinafter referred to as "serum-separation") by freeze and thaw, maintaining at high temperature for a long period, or repetition of freezing and heating to high temperature. Also, the aqueous gel has a defect that the partial gelation occurs easily, and therefore it is difficult to obtain a uniform aqueous gel.
An object of the present invention is to provide a process for preparing an aqueous gel, which can solve the above-mentioned defects.
As an aqueous gel composition containing perfume, a composition prepared by dispersing a perfume into a conventional aqueous gel such as carrageenan, agar, or the like, is mainly used.
However, the conventional aqueous gel composition has the following defects.
(1) The gelation of the composition is carried out by dissolving the perfume in the aqueous gel with heating at 60.degree. to 80.degree. C. and cooling it at room temperature. Therefore, perfumes having a poor heat-resistance are deteriorated by heating.
(2) The conventional aqueous gel per se is poor in transparency.
(3) The redissolution or the serum-separation phenomenon occurs at a temperature of more than about 50.degree. C.
(4) The decrease of gel strength or the serum-separation phenomenon occurs at low temperature.
Another object of the present invention is to provide an aqueous gel composition containing perfume or deodorant, which can be solved the above-mentioned defects, by utilizing the process for preparing an aqueous gel of the invention.
In general, as a lubricant for metal-processing, a mixture of graphite and oil, a metal soap, or the like is used and in order to improve the adhesion of the lubricant, mainly, a polymer such as a synthetic resin emulsion is added to the lubricant. A lubricant is coated on a steel plate to be processed and dried to form a lubricous film. The lubricant including a synthetic resin emulsion requires a lot of time for drying.
When drying is carried out at high temperature for rapid drying, the foaming phenomenon occurs, and accordingly, it is hard to obtain a uniform film. On the other hand, when drying is carried out at low temperature, the drying time is prolonged and the drying line is lengthened, thus resulting in practical disadvantage.
Further objects of the present invention are to provide a lubricant for metal-processing, which can solve the above-mentioned defects, by utilizing the process for preparing an aqueous gel of the invention and to provide a method for use thereof.